The present invention relates to a locking or security seal, and more particularly to an improved frangible locking or security seal of the type which easily becomes disintegral if an attempt it made to tamper with or defeat the seal or to operate, open or gain access to a protected item with which the seal has been associated.
Locking or security seals generally of the same or similar type as the improved locking seal of the present invention are well known. See for example commonly assigned U.S. Pat. Nos. 3,466,077; 3,467,427; 3,830,538; 4,229,031; 4,319,776 and 4,506,921.
In a first type of prior art seal, a shackle, comprising a flexible band, is inserted through apertures formed in relatively movable members of a lock, latch, operating handle or the like. Following such insertion, the terminus of a locking portion carried at one end of the shackle is inserted into a housing carried at the other end of the shackle. The housing contains facilities which prevent the withdrawal of the locking portion terminus following its insertion. The shackle interferes with attempts to operate or open the lock, latch, operating handle or other protected item.
Determined attempts to operate or open the protected item by overcoming the shackle's interference result in the shackle or some other portion of the seal becoming disintegral. Similarly, attempts to tamper with or defeat the seal also result in its becoming disintegral. If the seal is disintegral, a visual indication is given that an attempt--successful or otherwise--has been made to affect the protected item. This visual indication leads to inspection of the item or its contents to determine what, if anything, an interloper may have achieved.
In a second type of locking or security seal, access to or operation of a protected item is prevented by inserting the locking portion rather than the shackle or flexible band through apertures in relatively movable members on or associated with the protected item. The flexible band, which serves as a shackle in seals of the aforedescribed type, serves, in this type of seal, as a carrier for the locking portion and the housing. Attempts to open, operate or otherwise affect the protected item or to tamper with or defeat the seal result in the seal becoming disintegral.
Protected items are often containers, such as barrels or crates. Depending on whether the first type or the second type of seal is used, either the shackle or the locking portion of a seal may be inserted into apertures in an appropriate container closure, such as a hasp/staple combination or the locking lever of a band assembly or lock ring which holds a lid onto a barrel. If the seal is later noted to be disintegral, the container must be inspected to see if theft, tampering or adulteration have occurred.
Containers are typically shipped or transported on trucks, trains and airplanes. In transit, the containers may be subjected to random vibration or oscillatory motion. The forces incident to such motion are applied to the containers and may cause the container closure and the seal to move relatively in such a way that the walls and edges of the apertures through which the seal extends ultimately cut, shear or "saw through" the seal. When the seal is detected to be disintegral, inspection of the container and its contents is required, since it cannot be known whether this condition was caused by the act of an interloper or by a less sinister cause, such as vibration.
A general object of the present invention is an improved locking or security seal of the second type discussed above, in which the effects of forces on the seal during shipment are prevented from rendering the seal disintegral to give a false indication of tampering.